Joe Thornton had 7 points in 55 games in his first NHL season as 18y old. Lecavalier had 28 points in 82 games. I am not saying he should stay in NHL, but as long as he keeps progressing and he is not frustrated with his role and ice-time, it does not really matter for his long term development.
Joe Thornton had, in the OHL, 122 points in his draft year, and 19 points in 11 playoff games to boot.
There was no question that he knew how to put up points and he knew how to make plays.
Vincent Lecavalier had, in the QMJHL, 115 points in his draft year, and 41 points in 18 playoff games to boot.
There was no question that he knew how to put up points and he knew how to make plays.
Juraj Slafkovsky had 18 points in 11 games in TPS U20 games and 10 points in 31 games for TPS proper in Liiga in his draft year. In the playoffs he had 7 points in 18 games. Is 18 points in 11 U20 games good? I'm not sure, because the year before he had just 13 points in 16 games for the U20 team.
Putting aside games he played at 'midget' level, he's not a known quantity as a point producer. The comparisons to Thornton and Lecavalier don't help him look better. It is perfectly fine if he has a smoother trajectory but to deny that he's far behind is strange, to me. He is far behind NHL readiness if his role is to be a vedette not a background actor.